diff --git a/swh/vault/tests/test_backend.py b/swh/vault/tests/test_backend.py
--- a/swh/vault/tests/test_backend.py
+++ b/swh/vault/tests/test_backend.py
@@ -10,13 +10,12 @@
 
 from unittest.mock import patch
 
-from swh.core.tests.db_testing import DbTestFixture
 from swh.model import hashutil
 from swh.storage.tests.storage_testing import StorageTestFixture
 from swh.vault.tests.vault_testing import VaultTestFixture, hash_content
 
 
-class BaseTestBackend(VaultTestFixture, StorageTestFixture, DbTestFixture):
+class BaseTestBackend(VaultTestFixture, StorageTestFixture):
     @contextlib.contextmanager
     def mock_cooking(self):
         with patch.object(self.vault_backend, '_send_task') as mt:
diff --git a/swh/vault/tests/test_cache.py b/swh/vault/tests/test_cache.py
--- a/swh/vault/tests/test_cache.py
+++ b/swh/vault/tests/test_cache.py
@@ -5,7 +5,6 @@
 
 import unittest
 
-from swh.core.tests.db_testing import DbTestFixture
 from swh.model import hashutil
 from swh.storage.tests.storage_testing import StorageTestFixture
 from swh.vault.tests.vault_testing import VaultTestFixture
@@ -23,7 +22,7 @@
 TEST_CONTENT_2 = b'test content 2'
 
 
-class BaseTestVaultCache(VaultTestFixture, StorageTestFixture, DbTestFixture):
+class BaseTestVaultCache(VaultTestFixture, StorageTestFixture):
     def setUp(self):
         super().setUp()
         self.cache = self.vault_backend.cache  # little shortcut
diff --git a/swh/vault/tests/test_cookers.py b/swh/vault/tests/test_cookers.py
--- a/swh/vault/tests/test_cookers.py
+++ b/swh/vault/tests/test_cookers.py
@@ -21,7 +21,6 @@
 import dulwich.porcelain
 import dulwich.repo
 
-from swh.core.tests.db_testing import DbTestFixture
 from swh.loader.git.loader import GitLoader
 from swh.model import hashutil
 from swh.model.from_disk import Directory
@@ -102,7 +101,7 @@
         self.git_shell(*args, stdout=None)
 
 
-class BaseTestCookers(VaultTestFixture, StorageTestFixture, DbTestFixture):
+class BaseTestCookers(VaultTestFixture, StorageTestFixture):
     """Base class of cookers unit tests"""
     def setUp(self):
         super().setUp()